<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>高级选择器练习</title>
    <link rel="stylesheet" href="../css/ex.css">
</head>
<body>
<ul id="list">
    <li>
        <span>1</span>
    </li>
    <li>
        <span>2</span>
    </li>
    <li>
        <span>3</span>
    </li>
    <li>
        <span>4</span>
    </li>
    <li>
        <span>5</span>
    </li>
</ul>

<a href="#" id="link">超链接1 </a>

<img src="https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1574330127966&di=9b8839b9873d5bfaca9b23afd7793a0c&imgtype=0&src=http%3A%2F%2Fc-ssl.duitang.com%2Fuploads%2Fpeople%2F201806%2F27%2F20180627111248_mYkBX.jpeg">

<b id="b">粗体</b>

<br><br>

<button class="btn">登陆</button>

<input type="text" class="uame" placeholder="请输入信息">
</body>
</html>